1. Field
The present disclosure generally relates to processes for manufacturing composite structures, and deals more particularly with compaction of composite laminate stringers on contoured mandrel surfaces.
2. Background
Elongate composite members such as stringers used in the aircraft industry may be contoured in one or more planes along their length to conform to the curvature of a structure such as a fuselage skin. Contouring of a stringer may be accomplished using a compactor to compact an uncured stringer layup against contoured surfaces of a mandrel, such as a cure tool. Flexible compactors have been developed which flex or bend, allowing them to conform to contoured tool surfaces during the compaction process.
Depending on the degree of tool contour, the uncured stinger layup may develop wrinkles as it is being compacted against the tool, particularly near the center of curvature or greatest contour of the tool. This wrinkling occurs as a result of bending of the layers of composite material nearest the contoured tool surface, placing them in compression. Compression of the material in this manner causes excess material to accumulate and bunch into wrinkles. Wrinkling may have an undesired effect on the performance of the cured stringer.
Accordingly, there is a need for a method of compacting uncured composite members, such as stringers, on contoured tools, which controls material wrinkling. There is also a need for a method of compacting a stringer on a cure tool using a flexible compactor that reduces the size of the wrinkles while distributing the wrinkles generally uniformly along the length of the stringer.